CN108885043B

CN108885043B - Device for metering carbon dioxide snow

Info

Publication number: CN108885043B
Application number: CN201780019095.3A
Authority: CN
Inventors: 埃米利安·弗雷尔
Original assignee: Messer France SAS
Current assignee: Messer France SAS
Priority date: 2016-03-26
Filing date: 2017-03-22
Publication date: 2020-09-29
Anticipated expiration: 2037-03-22
Also published as: RS60694B1; HUE050486T2; EP3433552B1; DE102016003799A1; PL3433552T3; CN108885043A; PT3433552T; ES2806807T3; EP3433552A1; SI3433552T1; LT3433552T; WO2017167620A1

Abstract

The invention relates to a device for metering carbon dioxide snow, comprising a storage container and a discharge opening arranged at the base of the storage container. A horizontally movable slide base is arranged in the region of the discharge opening, by means of which slide base the discharge opening can be opened and closed. A horizontally movable separating base is positioned vertically at a distance from the slide base, the separating base being movable within the storage container. After filling the storage container with carbon dioxide snow, a metered amount of carbon dioxide snow between the separation base and the slide base is separated by the separation base, which amount is discharged via the movement of the slide base into its open position. The invention allows for the discharge of precisely metered amounts of carbon dioxide snow.

Description

Device for metering carbon dioxide snow

A device for metering carbon dioxide snow, which device has a storage container to which a supply line for carbon dioxide in liquid or snow-like form and a gas extraction line for discharging carbon dioxide gas open, and which is equipped with a discharge unit for discharging the metered carbon dioxide snow.

In order to be able to rapidly freeze surfaces, in particular food products, these surfaces are sprayed with a cryogenic refrigerant, such as liquid nitrogen or carbon dioxide snow. In this case, the treatment is preferably carried out in a freezing tunnel by means of injection nozzles or so-called snow horns.

In the snow horn, the carbon dioxide snow is produced by expanding liquid carbon dioxide using the joule-thomson effect. Here, the snow horn comprises an expansion element in the form of a nozzle, which is usually arranged in the top of the snow horn above a vertically arranged funnel. The pressurized liquid carbon dioxide is expanded at the expansion nozzle to a pressure below 5.18 bar, for example 1 bar, wherein a mixture of carbon dioxide gas and carbon dioxide snow is produced. The carbon dioxide snow falls under gravity into the hopper and onto the surface for cooling. However, when such a snow horn is used, the large amount of carbon dioxide gas simultaneously generated during expansion causes the lighter snow particles to swirl and thus causes the snow particles to spread widely upstream of the opening of the snow horn.

Attempts have been made to make the snow particles more densely packed using mechanical devices such as funnels or guide plates as described in EP 1188715A 1, US 4415346A or GB 294584 a. However, here, the carbon dioxide snow tends to agglomerate on the mechanical devices and impair the operation of said devices.

EP 2363377 a1 has disclosed a snow horn in which a conveying screw is arranged between an expansion chamber and a discharge opening. The conveyor screw ensures that the gas stream generated during expansion is separated from the carbon dioxide snow and that the carbon dioxide snow is transported precisely to the place of use. In this way, the carbon dioxide snow can be supplied to the consumer without being swirled by the gas flow. However, the supply of carbon dioxide is continuously ongoing; such a device exhibits only limited applicability for the targeted cooling of individual products which are transported through a cooling tunnel, for example on a conveyor belt.

US 4145894 a has disclosed an apparatus for distributing snow of carbon dioxide over a product in which the liquid carbon dioxide is expanded in a storage vessel. The carbon dioxide snow produced here is collected in a storage container, while the carbon dioxide gas produced is dissipated via an exhaust line. A cellular wheel brake is arranged on the base of the storage container, by means of which cellular wheel brake carbon dioxide snow from the storage container can be applied in a predetermined amount to the products located therebelow.

EP 0478316B 1 describes an apparatus for treating food products with carbon dioxide snow, in which apparatus the base of a storage container equipped with a supply of liquid carbon dioxide is equipped with a perforated plate and a wire mesh extends over the perforated plate. The wire mesh retains the carbon dioxide snow produced during expansion of the liquid carbon dioxide in the storage vessel. During use of the apparatus, the wiper is used to squeeze the snow of carbon dioxide through the holes in the wire mesh and the openings in the perforated plate, which then falls onto the surface of the product for disposal.

In the latter two plants, however, there is still a risk of carbon dioxide snow agglomerating in the cellular wheel brakes or in the holes of the wire mesh, or moisture from the surrounding atmosphere freezing there and thus impairing the functionality of the equipment.

The object of the invention is therefore to create a device for metering as precisely as possible a quantity of carbon dioxide snow, in the case of which the supply of carbon dioxide snow onto the product is not interrupted by the gas flow, while at the same time the risk of functional impairment due to caking of the carbon dioxide snow or freezing of moisture to solids is minimized.

Said object is achieved by the device of the invention.

The device of the type and purpose mentioned in the introduction is therefore characterized in that the discharge unit comprises a discharge opening arranged at the base side of the storage container; a horizontally movable slide base that interacts with the discharge port and that is movable between a first position in which the slide base closes the discharge port of the storage container and a second position in which the slide base opens the discharge port; and at least one likewise horizontally movable separating base arranged above and spaced apart from the slide base.

A supply line connected to a carbon dioxide source opens into the interior of a vertically arranged storage vessel, for example in the form of a tube. The supply line is, for example, a supply line for liquid carbon dioxide, which opens into the interior of the storage container at an expansion nozzle. The storage container has a discharge opening on its lower end side, which can be closed by a slide base. The discharge port extends over a portion of the base surface of the storage container or over the entire base surface of the storage container. The slide base is a horizontally movable or pivotable element, for example a metal plate, which is adapted to the size and shape of the discharge opening. In the closed position, the slide base extends completely or partially into the discharge opening and closes it to such an extent that the carbon dioxide snow supplied to or produced in the storage container cannot escape from the discharge opening or can escape only to a negligible extent, but is collected in the storage container above the slide base. In the open position, the slide base opens the discharge port, and the carbon dioxide snow in the storage container located above the slide base falls out of the storage container.

The separating base arranged above the sliding base is an element, for example a thin, dimensionally stable metal sheet, which can be displaced or pivoted horizontally into the interior of the storage container. The separating base can be moved by the drive from a first position (also referred to herein as "open position") in which the separating base is located outside the interior space of the storage container, to a second position (also referred to herein as "closed position") in which the separating base closes a cross section of the interior space of the storage container in a snow-tight manner and thus separates the carbon dioxide snow in that part of the storage container which is located below the separating base (also referred to herein as "metering section") from the remaining carbon dioxide snow above the separating base. At the same time, the separating base in its closed position prevents carbon dioxide snow from falling from the upper region of the storage container into the metering section. Therefore, when the slide base is moved to the open position, only the portion of the carbon dioxide snow located in the metering portion falls out of the storage container.

Thus, by the alternate actuation of the separating and sliding bases, a quantity of carbon dioxide snow defined by the volume of the metering portion is expelled, without for example causing the snow particles to be swirled by the carbon dioxide gas generated at the expansion nozzle during the expansion of the liquid carbon dioxide. Carbon dioxide is continuously supplied to the storage vessel via a supply line, wherein the generated carbon dioxide gas is discharged via a gas withdrawal line.

In a preferred embodiment of the invention, the slide base and/or the at least one separating base is equipped with a drive unit. A drive unit, for example equipped with an electric motor, controls the automatic movement of the slide base or the separating base from the respective open position to the respective closed position and back.

A particularly advantageous embodiment of the invention provides that the vertical spacing between the slide base and the separating base is variable. For example, for this purpose, the storage container comprises two parts which are vertically displaceable relative to one another, wherein the sliding base is arranged in the lower part and the separating base is arranged in the upper part. By displacement of the two parts relative to each other, the vertical spacing between the slide base and the separation base can be varied in a continuous manner, and thus also the volume of the metering part. The movement of the two parts relative to each other is effected manually or in a motor-driven manner. In a particularly preferred embodiment, the two parts of the storage container engage each other in a telescopic manner and can be displaced relative to each other in a continuously variable manner along their common longitudinal axis.

A particularly advantageous embodiment of the invention provides that the discharge unit has two or more separating bases which are arranged vertically spaced apart from one another, the separating bases being movable independently of one another. By means of a plurality of separating pedestals, the amount of carbon dioxide snow discharged can be varied in a targeted manner and adapted to the respective requirements. In particular, in this way the amount of carbon dioxide can be adapted to the size of the product to be cooled and/or to the refrigeration requirements of the respective cooling task without having to perform cumbersome changeover of the apparatus for this purpose.

A preferred use of the device according to the invention is to bring the surface of the product to a low temperature or to maintain the surface of the product at a low temperature, for example during transport. A particularly preferred use is in cooling or maintaining low temperatures of food products such as, but not limited to, doughs, meats, fish, fruits and vegetables. Conversely, other products (e.g., chemicals or pharmaceuticals) may also be cooled or maintained at a low temperature. The apparatus according to the invention can in particular also be arranged in a cooling tunnel in order to apply the carbon dioxide snow onto the surface of the product.

Exemplary embodiments of the invention will be discussed in more detail on the basis of the accompanying drawings, in which:

figure 1 shows a vertical cross-section of the apparatus according to the invention,

figures 2a to 2f show different working steps during operation of the device of figure 1,

figure 3 shows a device according to the invention in another embodiment,

fig. 4 shows a device according to the invention in a further embodiment.

The apparatus 1 shown in fig. 1 comprises a storage vessel 2 with well insulated walls. A supply line 3 for supplying liquid carbon dioxide, at the end of which an expansion nozzle is arranged, opens into the interior of the storage vessel 2. A direct supply of carbon dioxide snow, of the type described in EP 2363377 a1, instead of the supply line 3 for liquid carbon dioxide as shown here, is also conceivable within the context of the present invention. A plurality of supply lines for liquid carbon dioxide and/or carbon dioxide snow are also possible. A discharge unit 4 (described in more detail below) is located in a lower region of the storage vessel 2 and a gas extraction line 5 opens into an upper region of the storage vessel 2.

The discharge unit 4 comprises a discharge opening 7 which is arranged at the lower end side 6 of the storage container 2 and which completely or partially fills the end side 6 and which can be closed by a horizontally movable slide base 8. The slide base 8 is actuated by a drive unit 9, which comprises for example an electric motor and which can be actuated by a central controller (not shown here). In the position shown in fig. 1, the slide base 9 closes the discharge opening 7. The discharge openings 7 can be connected, if desired, by a metering funnel (not shown here).

Arranged vertically spaced from the sliding base 8 is a likewise horizontally displaceable or pivotable separating base 11, for example a thin metal sheet or a displaceable base, whose edge facing the interior space of the storage container can be formed in the manner of a knife edge. The separating base 11 can be moved or pivoted by means of a drive unit 12 which is electrically driven, for example, from an open position, in which the separating base 11 is located outside the interior space of the storage container 2, to a closed position, in which the separating base 11 divides the interior space of the storage container 2 in a snow-tight manner into two partial volumes, wherein the lower volume extending between the separating base 11 and the slide base 9 defines the metering section 10.

The drive unit 9 and/or the drive unit 12 can interact with a sensor device 14 which detects the position of the product (not shown here) to be applied with the carbon dioxide snow or of the container (likewise not shown) to be filled with the carbon dioxide snow in order to allow targeted application of the carbon dioxide snow to the product surface or filling of the container with the carbon dioxide snow.

Fig. 2a-f show various operating states of the device 1. During ongoing operation of the apparatus 1 according to the invention, carbon dioxide snow 15 is continuously supplied to the storage vessel 2. This is achieved by supplying liquid carbon dioxide from a storage tank (not shown here) via a supply line 3, which liquid carbon dioxide is expanded in a storage vessel 2 at an expansion nozzle arranged at the opening point of the supply line 3 to a pressure below 5.18 bar, preferably to atmospheric pressure (1 bar), and becomes a mixture consisting of carbon dioxide snow and carbon dioxide gas. While the carbon dioxide gas generated by expansion or sublimation in the storage container 2 is discharged via the gas extraction line 5, the majority of the carbon dioxide snow 15 is collected inside the storage container 2.

In the operating state shown in fig. 2a, the separating base 11 is arranged on the side of the inner space of the storage container 2. As the snow-like carbon dioxide is continuously produced or supplied, the internal space above the slide base 8 of the storage container 2 is gradually filled with carbon dioxide snow 15.

By actuation of the drive unit 12, the separating base 11 is moved in the direction of arrow 16 into the closed position (fig. 2 b). Thus, the carbon dioxide snow 15 located in the metering portion 10 of the storage container 2 is separated from the remaining carbon dioxide snow 15 located within the storage container 2.

By actuation of the drive unit 9, the slide base 8 is displaced or pivoted in the direction of arrow 17 into its open position and thus opens the discharge opening 7 (fig. 2 c). Thus, the carbon dioxide snow 15 located in the metering section 10 falls out of the storage container 2, while the remaining carbon dioxide snow 15 remains in the storage container via the separating base 11 (fig. 2 d). The discharged carbon dioxide snow falls, for example, directly on the product for cooling or in a container or is supplied to a metering hopper (not shown here).

By a further actuation of the drive unit 9, the slide base 8 is then moved back into the closed position, as indicated by arrow 18 (fig. 2 e). Thus closing the discharge opening 7 again. Subsequently, by the drive of the drive unit 12, the separating base is moved in the direction of arrow 19 into its open position (fig. 2f) and the carbon dioxide snow 15 falls from the upper part of the storage container 2 into the metering portion 10, as indicated by arrow 21. The carbon dioxide snow discharged through the discharge opening 7 is replenished by uninterrupted supply or uninterrupted production at the supply line 3, whereby the operating state shown in fig. 2a is started again.

In the embodiment of the device 22 according to the invention shown in fig. 3, the parts acting in the same way are denoted by the same reference numerals as in the device 1. The apparatus 22 differs from the apparatus 1 only in that a plurality of separating

bases

11a, 11b, 11c, in the exemplary embodiment three, are provided instead of a single separating base 11, each arranged vertically spaced apart from one another. The separating

bases

11a, 11b, 11c, which are of the same construction as the separating base 11, can be moved independently of one another by means of

drive units

12a, 12b, 12 c.

The plurality of

separation bases

11a, 11b, 11c allows the metered amount of carbon dioxide snow to be changed. Depending on the desired amount, one of the

separation bases

11a, 11b or 11c is selected to separate the carbon dioxide snow located in the storage container 2. The metered amounts correspond respectively to the amount of carbon dioxide snow in the volume between the slide base 8 and the respective selected

separation base

11a, 11b, 11 c.

The device 24 shown in fig. 4 allows a continuously variable adjustment of the metered amount of carbon dioxide snow to be discharged. In this case, the same components as those in the

apparatuses

1 and 22 are also denoted by the same reference numerals. The device 24 has a feed container 25 which is divided into two

parts

26, 27 which are designed to be displaceable relative to each other in a telescopic manner, as indicated by the arrow 28. The slide base 8 is arranged in the lower portion 26 and the separate base 11d equipped with the driver 12d is arranged in the upper portion 27. The slide base 8 and the separation base 11d are constructed in the apparatus 24 in the same manner as in the apparatus 1. In order to vary the amount of carbon dioxide snow discharged, the lower portion 26 is displaced with respect to the upper portion 27 until a volume forming the metering portion 10 between the slide base 8 and the separation base 11d is sufficient to contain the required metered amount of carbon dioxide. The displacement of the two

parts

26, 27 relative to each other is carried out in a continuously variable manner and can be carried out manually or by means of a drive unit not shown here.

The invention allows an accurate metering of the amount of carbon dioxide with respect to corresponding devices of the prior art and exhibits a lower susceptibility to failure due to the formation of agglomerated snow or water ice bodies. The invention is particularly suitable for doses of snow of carbon dioxide, for example in excess of 100g, preferably in excess of 500g, to be applied to objects for treatment at short intervals lasting a few seconds. Furthermore, the carbon dioxide gas generated simultaneously with the carbon dioxide snow is discharged immediately after formation without mixing with the surrounding atmosphere. Therefore, the carbon dioxide gas has a high purity, and can be easily further used or reused. Furthermore, the device according to the invention also allows for the precise metering of the carbon dioxide snow in order to fill the coolant compartment of the transport container used for transporting the product to be cooled.

List of reference numerals

1 apparatus

2 storage container

3 supply line

4 discharge unit

5 gas extraction line

6 lower end side

7 discharge port

8 sliding base

9 drive unit

10 metering section

11, 11a, 11b, 11c, 11d separating base

12, 12a, 12b, 12c, 12d drive unit

13 -

14 sensor device

15 carbon dioxide snow

16 arrow head

17 arrow head

18 arrow head

19 arrow head

20 -

21 arrow head

22 device

23 -

24 device

25 feed vessel

26 lower part

27 upper part

28 arrow head

Claims

1. A device for metering carbon dioxide snow, which device has a storage container (2) to which a supply line (3) for carbon dioxide in liquid or snow-like form and a gas extraction line (5) for discharging carbon dioxide gas open and which is equipped with a discharge unit (4) for discharging the metered carbon dioxide snow (15),

it is characterized in that the preparation method is characterized in that,

the discharge unit (4) comprises a discharge opening (7) arranged at the base side of the storage container (2); a horizontally movable slide base (8) which interacts with the discharge opening (7) and which is movable between a first position, in which it closes the discharge opening (7) of the storage container (2), and a second position, in which it opens the discharge opening (7); and at least one horizontally movable separating base (11, 11a, 11b, 11c, 11d) which is arranged above the sliding base (8) of the storage container (2) and which is movable from a first position, in which it divides the interior space of the storage container (2) into two partial volumes, into a second position, in which it is spaced apart from the interior space of the storage container (2), wherein the vertical spacing between the sliding base (8) and the separating base (11d) is variable.

2. The device according to claim 1, characterized in that the slide base (8) and the separating base (11, 11a, 11b, 11c, 11d), or the separating base (11a, 11b, 11c, 11d), are each provided with a drive unit (9, 12, 12a, 12b, 12c, 12 d).

3. The device according to claim 1, characterized in that the storage container (2) comprises two parts (26, 27) which are displaceable relative to each other in a telescopic manner, wherein the sliding base (8) is arranged in the lower part (26) and the separating base (11d) is arranged in the upper part (27).

4. The apparatus according to claim 1, characterized in that the discharge unit (4) has a plurality of separating bases (11a, 11b, 11c) arranged one above the other, which are horizontally movable independently of each other.